In resent years, demands placed on resins for optical use (optical resins) are getting higher and higher, where the resins having heat resistance and high transparency are demanded. However, conventional optical resins have various disadvantages. For example, poly(methyl methacrylate) has excellent optical properties, such as high transparency and small birefringence, but has a disadvantage of low heat resistance. In contrast, as a method for producing an optical resin with high heat resistance and excellent transparency, for example, Patent Document 1 proposes a method for producing a hydrogenation product of a polymer formed by ring-opening polymerization of a cyclic olefin, which includes ring-opening metathesis polymerization of a cyclic olefin derived from petroleum, followed by hydrogenation of the resulting product. Patent Document 2 proposes a method for producing cycloolefin copolymers, each being an alicyclic hydrocarbon type copolymer, which includes copolymerizing a cycloolefin and a linear olefin in the presence of a certain catalyst.